Effect of local relaxation on the binding energy of group-V donors in silicon.

Abstract

With use of a first-principles pseudoimpurity theory and a variational method, the binding energies of the shallow donors P, As, Sb, and Bi in Si are estimated; a multivalley effective-mass equation, incorporating the effect of local relaxation due to the difference in sizes between the host and impurity atoms, has been used. The extent of this relaxation is compared with results available in the literature. The substitutional donors As, Sb, and Bi are found to occupy nearly the same volume of the Si atom in the lattice. The model of the lattice-relaxation effect as proposed by Pantelides and Sah [Phys. Rev. B 10, 638 (1974)] is used.